{
  "node": {
    "id": "term:ul-9540",
    "type": "Term",
    "label": "UL 9540",
    "properties": {
      "id": "ul-9540",
      "name": "UL 9540",
      "section": "topic-standards-stationary",
      "definition": "The North American product safety standard for a complete energy storage system — battery, inverter and controls together — as opposed to UL 9540A, which is the test method for its thermal-runaway behaviour. Listing to UL 9540 is what most US fire codes require for installation.",
      "related": [
        "ul-9540a",
        "nfpa-855",
        "stationary-storage",
        "inverter",
        "pas-63100"
      ],
      "url": "https://lemonergy.com/learn/glossary/ul-9540/",
      "mentions": []
    }
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      "id": "edge:3823",
      "source": "term:ul-9540",
      "target": "term:ul-9540a",
      "type": "relatedTo",
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        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
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      "type": "relatedTo",
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        "meaning": "Related context; not a causal claim"
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      "id": "edge:3825",
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      "target": "term:stationary-storage",
      "type": "relatedTo",
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        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
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      "id": "edge:3826",
      "source": "term:ul-9540",
      "target": "term:inverter",
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        "meaning": "Related context; not a causal claim"
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      "target": "reference:ul-storage",
      "type": "cites",
      "properties": {
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        "scope": "direct technical reference"
      }
    }
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  "neighbors": [
    {
      "id": "topic:topic-standards-stationary",
      "type": "Topic",
      "label": "Stationary, industrial and product standards",
      "properties": {
        "id": "topic-standards-stationary",
        "name": "Stationary, industrial and product standards",
        "lede": "Safety and performance standards for portable, industrial and grid batteries, their electronics and their installation.",
        "context": "Match scope to product and installation.",
        "example": "A cell-level test does not establish fire performance or commissioning requirements for a complete installation.",
        "lesson_url": "https://lemonergy.com/learn/fundamentals/battery-basics/",
        "lesson_label": "Open battery basics"
      }
    },
    {
      "id": "term:ul-9540a",
      "type": "Term",
      "label": "UL 9540A",
      "properties": {
        "id": "ul-9540a",
        "name": "UL 9540A",
        "section": "topic-standards-stationary",
        "definition": "A test method, not a pass/fail standard, that characterises thermal runaway and propagation in stationary storage at cell, module, unit and installation level. Fire codes use its data to decide spacing and suppression for a storage site.",
        "related": [
          "thermal-propagation",
          "stationary-storage",
          "fire-suppression",
          "propagation-test",
          "nfpa-855"
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        "url": "https://lemonergy.com/learn/glossary/ul-9540a/",
        "mentions": [
          "thermal-runaway"
        ]
      }
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      "id": "term:nfpa-855",
      "type": "Term",
      "label": "NFPA 855",
      "properties": {
        "id": "nfpa-855",
        "name": "NFPA 855",
        "section": "topic-standards-stationary",
        "definition": "The US fire-protection standard for the installation of stationary energy storage systems: spacing between units, maximum energy per fire area, suppression, explosion control and the UL 9540A data needed to deviate from the defaults.",
        "related": [
          "ul-9540a",
          "stationary-storage",
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        "mentions": []
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      "id": "term:stationary-storage",
      "type": "Term",
      "label": "Stationary storage",
      "properties": {
        "id": "stationary-storage",
        "name": "Stationary storage",
        "abbr": "BESS",
        "aka": [
          "battery energy storage system",
          "ESS"
        ],
        "section": "topic-applications",
        "definition": "Batteries installed in a fixed place — a container at a solar farm, a cabinet in a home — to shift energy in time or support the grid. LFP cells dominate because cost per cycle and safety matter more than mass.",
        "related": [
          "lfp",
          "energy-management-system",
          "inverter",
          "energy-arbitrage",
          "long-duration-storage",
          "ul-9540a"
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        "url": "https://lemonergy.com/learn/glossary/stationary-storage/",
        "mentions": []
      }
    },
    {
      "id": "term:inverter",
      "type": "Term",
      "label": "Inverter",
      "properties": {
        "id": "inverter",
        "name": "Inverter",
        "aka": [
          "power conversion system",
          "PCS"
        ],
        "section": "topic-pack",
        "definition": "The power electronics that turn the battery’s DC into AC for a motor or the grid, and back again for charging. In stationary storage it is called the power conversion system and its rating in kW or MW sets the system’s power independently of the battery’s energy.",
        "related": [
          "pre-charge",
          "dc-dc-converter",
          "stationary-storage",
          "energy-management-system",
          "direct-current",
          "iec-62477-1"
        ],
        "url": "https://lemonergy.com/learn/glossary/inverter/",
        "mentions": []
      }
    },
    {
      "id": "term:pas-63100",
      "type": "Term",
      "label": "PAS 63100",
      "properties": {
        "id": "pas-63100",
        "name": "PAS 63100",
        "aka": [
          "PAS 63100:2024"
        ],
        "section": "topic-standards-stationary",
        "definition": "The UK specification, published by BSI in 2024, for fire protection of battery storage in homes. It bars batteries from bedrooms, escape routes, lofts and voids, requires interlinked smoke detection where they sit in rarely visited spaces, and caps energy at 20 kWh per enclosure and 40 kWh per dwelling, or 80 kWh outdoors or in a separated garage.",
        "related": [
          "stationary-storage",
          "nfpa-855",
          "fire-suppression",
          "iec-62485",
          "thermal-runaway"
        ],
        "url": "https://lemonergy.com/learn/glossary/pas-63100/",
        "mentions": [
          "kilowatt-hour",
          "enclosure"
        ]
      }
    },
    {
      "id": "reference:ul-storage",
      "type": "Reference",
      "label": "Energy Storage System Testing and Certification",
      "properties": {
        "title": "Energy Storage System Testing and Certification",
        "publisher": "UL Solutions",
        "url": "https://www.ul.com/services/energy-storage-system-testing-and-certification",
        "type": "Official documentation",
        "scope": "System safety scope of UL 9540 and relationships to battery and power-conversion standards.",
        "accessed": "2026-10-27"
      }
    }
  ]
}